In every cold climate region, people often keep airplanes and other vehicles, including diesel powered heavy equipment outdoors year round. Similarly, stationary engines such as those used in electrical generation are often kept exposed to the elements. In the winter, these engines become extremely difficult to start without some type of preheating. The heat is typically applied to warm the engine oil to thin it and to warm the fuel intake components so that vaporization of the fuel is more reliable. Many automobiles have electrical block heaters or pad heaters that heat the engine's coolant or oil pan. A block heater causes the warmed coolant to circulate within the engine, thereby warming the components and the oil. Heating the oil pan warms the oil, which thins it and makes it flow easily through the engine on startup. These heaters are seldom found on airplanes. Even if such heaters are installed on the airplane, when the airplane is parked at a remote airstrip, there may not be any electricity to operate the heater.
Instead of providing electrical outlets for electric engine heaters, some airports keep portable engine heaters. These heaters are usually a burner type heater using some type of liquid fuel such as gasoline or propane to warm air and blow it over an engine. Many models use electric fans to force the warmed air over the engine. Some even provide a small gasoline powered generator to power the fan.
Examples of heaters are found in U.S. Pat. Nos. 4,268,248 Wilbur et al., and 3,454,266 to Mattinkly. Both Patents show heaters used to warm airplane engines. The Mattinkly Patent uses a battery powered fan to blow warm air produced by a gas fired burner. The Wilbur Patent discloses a smaller, more portable, burner that uses disposable gas cylinders as a fuel source. This device uses a portion of the hot exhaust gas to warm the gas cylinder. It also uses a battery driven fan. Both devices are considered portable, but they weigh a considerable amount and take up considerable space in an airplane. Besides the weight and size problems, the devices that use batteries to operate the fan use power that could be used to crank the engine of the plane. In cold weather, batteries operate poorly and operating a fan to warm the engine may tax the battery to the point where it will not properly crank the engine. Carrying a second battery simply to operate the fan adds that much more weight to these devices. Additionally, as noted above, the Wilber Patent uses disposable gas cylinders. The empty cylinders will often be left at the remote sight, such as airstrips, lakes and campgrounds, which adds to the already serious waste problem. Another drawback in these designs is that these heaters operate using only one type of fuel. Finally, they are not readily adaptable, in an emergency, into a survival stove. They cannot readily be used to heat water, melt snow or cook a meal.